Robert Lucas is rightfully credited with having changed the course of macroeconomic theory. The aim of this paper is to document his transformation from a potential contributor to Keynesian macroeconomics to the master builder of an alternative paradigm, equilibrium macroeconomics. I reconstruct Lucas’s theoretical journey as involving seven steps: (1) his pre-macroeconomic years, (2) his early work as a macroeconomist, jointly with Rapping, (3) the ‘Expectations and the Neutrality of Money’ 1972 article, (4) his inaugural equilibrium model of the business cycle, (5) his all-out attack on Keynesian macroeconomics, (6) the passing of the baton to Kydland and Prescott, and (7) his standpoint after the victory of the approach he so much contributed to launch